The multipass help command without an argument will list all the available commands with a brief explanation. It accepts a <command> argument to get detailed help for the command in question.

$ multipass help
Usage: multipass [options] <command>
Create, control and connect to Ubuntu instances.
This is a command line utility for multipass, a
service that manages Ubuntu instances.
Options:
-h, --help Display this help
-v, --verbose Increase logging verbosity, repeat up to three times for more
detail
Available commands:
copy-files Copy files between the host and instances
delete Delete instances
exec Run a command on an instance
find Display available images to create instances from
help Display help about a command
info Display information about instances
launch Create and start an Ubuntu instance
list List all available instances
mount Mount a local directory in the instance
purge Purge all deleted instances permanently
recover Recover deleted instances
shell Open a shell on a running instance
start Start instances
stop Stop running instances
umount Unmount a directory from an instance
version Show version details

Using the --help option has the same result.

--verbose passed to any command will increase its output verbosity and you can repeat it (up to three times) to get even more output. By default, only errors will be displayed, with -v warnings would be added, -vv enables informational messages and -vvv will print out debugging information.